Accepting: Accepting that one is having fearful/nervous reactions is essential. One can then detach from the automatic cycle enough to reduce and diffuse it. There are many useful physical and mental exercises one can use here.

Using practical relaxation skills: These need to be practised and used regularly.

Making use of the nerves: It's important to keep in mind the usefulness of some nervous tension - one needs to be keyed up to achieve peak performance, as any athlete will tell you.

Preparing well: People who take an exam or interview seriously will know very well how to do their ordinary preparation - getting to know the relevant information and ideas, the practical skills and so on. This is a basic of exam and interview skill. However, it's common for people to simultaneously think of all the things that can and will go wrong and to rehearse feeling nervous about that - to do a kind of negative self hypnosis as it were. Good preparation involves mental rehearsal, both of doing things well and of recovering after things go temporarily wrong. Perfect performances are often made up of concealed mistakes.

Using imagination: The skill of mental rehearsal using both literal and metaphorical scenarios helps one to develop a level of automatic competence and confidence in the situation and keeps one in touch with mental flexibility.

Confidence: Is not a thing you have in certain limited and measurable qualities, but a practical skill that belongs to a context or series or contexts. Hence one needs to practise the skill of confidence and the ability to adapt the feeling to changing circumstance.